Researchers tested thalamic deep brain stimulation (CT-DBS) in mice, starting at one microamp and increasing to 200 microamps to find the seizure threshold.
Surprisingly, seizures occurred 2.2% of the time during prolonged stimulation at lower currents, even at 20 microamps. This was unexpected, as noted by Francisco Flores and Isabella Dalla Betta, co-leads of the study published in Brain Stimulation.
Stimulation frequency didn’t affect seizure risk, but higher currents increased the chance of seizures. For example, seizures occurred in 5 out of 190 tests at 50 microamps and 2 out of 65 tests at 100 microamps. Seizures happened faster with higher currents and when both sides of the thalamus were stimulated.
Some mice showed no seizure-like behavior, while others were hyperactive. The reason for varying seizure responses in different mice is unclear. Future research will explore how brain states influence seizure risk during thalamic stimulation.
The study authors recommend closely monitoring EEG for seizures during CT-DBS, especially in awake subjects. Matt Wilson co-authored the paper, which included contributions from Dalla Betta, Flores, Brown, and other researchers.
The study found that stimulating the thalamus can increase the risk of seizures, especially at higher current levels. Monitoring EEG for seizures is important during this type of stimulation.
Journal reference :
- Francisco J. Flores, Isabella Dalla Betta, et al., Electrographic seizures during low-current thalamic deep brain stimulation in mice. Brain Stimulation. DOI:10.1016/j.brs.2024.08.002 .